TST: Add test for reduceat ufunc regression on zero-sized array
BUG: Fix ufunc.reduceat regression with empty index (gh-2892)
TST: Test that nansum(boolean array) is identical to sum(boolean array)
BUG: Fix nansum(boolean array) to be identical to sum(boolean array)
TST: Test for x.fill(tuple) where x is a struct array
BUG: Fix to allow x.fill(tuple) where x is a struct array
fixing Mark Wiebes merge conflict
move functions up to before where they are used
add missing argument
Fix ndindex issue

Call to ndindex() with no arguments results in a ValueError exception, whereas before commit ca27396b, a call with no arguments was allowed.
Issue is due to unneeded check for shape tuple size.
Add test for optional size argument for ndindex
Add test for __array_interface__
Undo previous fix for Mark's merge issue
Increment iter_descr ref